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Date:      Tue, 06 Jun 2000 11:21:08 -0400
From:      Nathan Vidican <webmaster@wmptl.com>
To:        Jim Conner <jconner@enterit.com>
Cc:        questions@freebsd.org
Subject:   Re: IP vs CNAME
Message-ID:  <393D16E4.D2E76C9A@wmptl.com>
References:  <FCEELIAEIIECDGKKJLMIMECHCAAA.troy@picus.com> <4.3.1.2.20000604022838.0195f9b8@mail.enterit.com>

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Jim Conner wrote:
> 
> At 11:11 PM 6/3/00 -0700, Doug Barton wrote:
> >Troy Settle wrote:
> >
> > > Oh man...  you like to pick nits.
> >
> >         The problem is, DNS is just that way. If you don't get it exactly
> > right,
> >it won't work.
> >
> > > I didn't think I'd have to go quite so
> > > far as to bore everyone with an SOA record.  But since you insist:
> > >
> > > @       IN      SOA     ns1.isp.net. hostmaster.isp.net. (
> > >               2000060401  10800  3600  3600000  86400 )
> > >         IN    MX  10   mailhost.isp.net.
> > >         IN    MX  20   spooler.isp.net.
> > >         IN    NS       ns1.isp.net.
> > >         IN    NS       ns2.isp.net.
> > > @       IN    CNAME    webhost.isp.net.
> > > www     IN    CNAME    webhost.isp.net.
> > > mail    IN    CNAME    mailhost.isp.net.
> > >
> > > Happy now?
> 
> He's right.  This zone file as-is won't work.  You have no A names
> here!!  Also, it appears you are using version 4.x syntax.  This zone file
> would never do for a current version of bind.
> 
> You have the origin specified to point to webhost.isp.net.  Unless you have
> an A record somewhere in another zone this will not work.
> 
> -Jim
> 
> >         Nope. That won't work either. I reiterate:
> >
> > > ** you can't combine
> > > ** CNAME RR's and other RR's for the same host.
> >
> >         Try actually loading up a zone file that looks like that and
> > you'll see
> >what I mean.
> >
> > > Actually, I don't use CNAMEs that often, and never realized this.
> >
> >         So why are we having this conversation? You obviously don't
> > understand
> >what I'm talking about, and you don't have enough background to be
> >disagreeing with me. I'm not trying to be rude, but I hate seeing people
> >give bad advice on a public list. Innocent users might be misled.
> >
> >
> >To Unsubscribe: send mail to majordomo@FreeBSD.org
> >with "unsubscribe freebsd-questions" in the body of the message
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Today's errors, in contrast:
> Windows - "Invalid page fault in module kernel32.dll at 0032:A16F2935"
> UNIX  - "segmentation fault - core dumped"
> Humanous Beingsus - "OOPS, I've fallen and I can't get up"
> -------------------------------
> Jim Conner
> NOTJames
> jconner@enterit.com

This message has gone a little off-topic, but since there's been so many
replies/(arguments), I've posted what my decision was. I decided to
stick with using CNAME's. Mainly for the purpose of ease of
administration. The zonefile as posted above is in fact similar to that
which I am actually using, and it does work. (No I'm not using Bind 4.x
either) It just depends on an A record <somewhere> for the CNAME to
point to; who said the CNAME has to point to a domain controlled by the
same DNS server? In my case, the configuration is as follows, just in
case anyone would care to see what I chose to do.

Every new site is using name-based hosting to one of several webservers.
Each 'pool' of virtual-hosts, (by pool I mean those using the same
webserver), has exactly the same DNS zonefile, my newaccount scripts
actually copy an existing one over. The zonefile looks like this:

@                       IN      SOA     ns.mydomain.net.
hostmaster.mydomain.net. (
                        2000050902
                        10800
                        3600
                        8432000
                        38400 )
                        IN      NS      ns.mydomain.net.
                        IN      NS      ns2.mydomain.net.
                        IN      MX 100  mail.mydomain.net.
			IN	MX 200  mail2.mydomain.net.
mail                    IN      CNAME   mail.mydomain.net.
www                     IN      CNAME   web001.mydomain.net.

The zone definition like this:

zone "whatever.com" {
	type master;
	file "zones/whatever.com.hosts";
};

And apache's virtualhost on web001.govital.net, contains the line:

NameVirtualHost	xxx.xxx.xxx.xxx:80

<VirtualHost whatever.com>
DocumentRoot "/some-dir"
</VirtualHost>


One of the primary reasons this works out for us, is that we can change
a single record per webserver, and not have to change the corrosponding
100s of domains  to match. I understand that using a CNAME means two DNS
lookups whereas using an A records needs one; but what if
web001.mydomain.net needed to be changed? It would be quick and easy
with a CNAME-based setup, but a big change-over if I were using
A-records. As fate would have it, we are planning on changing our
upstream provider, (which also means changing our IP blocks). We have a
one month overlap wherein we'll have service from both providers so we
can transfer the servers one-by one.
	In short, I guess my origional question would have been asked better if
I said "Would it make any difference to someone viewing
www.whatever.com, if it were hosted by name, or by IP address?" Thanks
for the help, and I appreciated all the feedback, but I think I'm just
going to continue as I am.

-- 
Nathan Vidican
webmaster@wmptl.com
Windsor Match Plate & Tool Ltd.
http://www.wmptl.com/


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